Low-cost high-performance planar back-gate CMOS
View Patent ↗A method of fabricating a high-performance planar back-gate CMOS structure having superior short-channel characteristics and reduced capacitance using processing steps that are not too lengthy or costly is provided. Also provided is a high-performance planar back-gate CMOS structure that is formed utilizing the method of the present invention. The method includes forming an opening in an upper surface of a substrate. Thereafter, a dopant region is formed in the substrate through the opening. In accordance with the inventive method, the dopant region defines a back-gate conductor of the inventive structure. Next, a front gate conductor having at least a portion thereof is formed within the opening.
1. A planar back-gate CMOS structure comprising:
a substrate having a back-gate conductor whose lateral dimension is defined by an opening located in an upper surface of said substrate;
a front gate conductor located entirely within said opening; and
source/drain regions located adjacent to opposite sides of said front gate conductor.
2. The planar back-gate CMOS structure of claim 1 wherein said substrate comprises a bulk semiconductor or a semiconductor-on-insulator.
3. The planar back-gate CMOS structure of claim 1 wherein said substrate is a semiconductor-on-insulator, wherein a top semiconductor layer under said opening has a thickness from about 5 to about 25 nm.
4. The planar back-gate CMOS structure of claim 1 further comprising at least one trench isolation region and a trench contact within said substrate.
5. The planar back-gate CMOS structure of claim 1 wherein said source/drain regions and optionally said front gate conductor include a silicide.
6. The planar back-gate CMOS structure of claim 1 further comprising a gate dielectric within said opening atop a thinned surface of said substrate.
7. The planar back-gate CMOS structure of claim 1 further comprising an interconnect structure, said interconnect structure including an interlevel dielectric having conductively filled vias and lines embedded therein.
8. The planar back-gate CMOS structure of claim 1 wherein a well region is located about said back-gate conductor, said well region is in electrical communication to the upper surface of said substrate though a trench contact.
9. The planar back-gate CMOS structure of claim 1 wherein said back-gate conductor has a dopant concentration from about 10 19 to about 10 21 atoms/cm 3 .